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Unit 1: Water: Exploring Solutions. Miss Shuey Chem Comm. Essential Questions. What techniques can we use to purify water? What are the physical properties of water? Why do some substances readily dissolve in water and others do not? - PowerPoint PPT Presentation
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M I S S S H U E YC H E M C O M M
UNIT 1: WATER: EXPLORING SOLUTIONS
ESSENTIAL QUESTIONS
• What techniques can we use to purify water?• What are the physical properties of water?• Why do some substances readily dissolve in
water and others do not?• How does chemistry contribute to effective water
treatment?
ARTICLE REVIEW
• Fish Kill Triggers Riverwood Water Emergency
SECTION A: SOURCES AND USES OF WATER
• Uses of water:1. _________________________2. _________________________3. _________________________4. _________________________5. _________________________6. _________________________7. _________________________8. _________________________9. _________________________10. _________________________
A.4 WATER SUPPLY AND DEMAND
• Family of four uses 390 gallons daily.• Direct water use – volume that can be directly
measured.• Indirect water use – hidden uses of water that
you may never have considered.• Ex. Slice of pizza??Figure 1.12
A5. WATER USE IN THE US
• For each region in the US, name the greatest single use of water.• A. the east b. the south c. the midwest• D. the west e. alaska f. hawaiiExplain the differences in how water is used in the east and the west. Think about where most people live and where most of the nation’s factories and farms are located. What other regional factors help explain the general patterns of water use?List two factors about the weather, economy, or culture that could explain the greatest water use within each of these six U.S. regions.
A.6 WHERE IS THE WORLD’S WATER?
• 97% of the world’s water.1. Ocean2. Glaciers
PHYSICAL STATES OF WATER
• Gaseous state: water vapor• Liquid state: lakes, rivers, oceans, clouds, and
rain.• Solid state: ice
CITY WATER
• Surface water: water supply originated in a river or other body of water.• Ground water: water in a well.
RURAL WATER
• Aquifer: water-bearing layer of rock, sand, or gravel, then pumped to the surface.
A.8 RIVERWOOD WATER USE
• Pg.22• http://
www.youtube.com/watch?v=xxNfJLMNS4E&list=FLHywkjQDas46hk_l2QAeKaA&feature=mh_lolz
SCIENTIFIC METHOD
Hypothesis – testable statementcontrols – remain constantvariable – is changed
Model – explanation of how phenomena occur and how data or events are related.Theory – broad generalization that explains a body of facts or phenomena.
ACCURACY AND PRECISION
• Accuracy – close to the expected value• Precision – a number of measurements close to
each other.
What is more accurate?Graduated cylinderOrBeaker
SIGNIFICANT FIGURES
• Indicates how precise a measurement is.rule example1. Zeros between other nonzero digits are significant
a. 50.3 m has three sig figsb. B. 3.0025 s has five sig figs
2. Zeros in front of nonzero digits are not significant.
a. 0.892 kg has three sig figsb. 0.0008 ms has one sig fig
3. Zeros that are at the end of a number and also to the right of the decimal are significant
a. 57.00 g has four sig figsb. B. 2.000000 kg has seven sig figs
4. Zeros at the end of a number but to the left of a decimal are significant if they have been measured or are the first estimated digit; if not they are NOT significant.
a. 1000 m may contain from one to four sig figs, depending on the precision of the measurement, in this book it will be assumed there is one sig fig.
b. 20 m has one sig fig (scientific notation will indicated sig fig number)
RULES FOR CALCULATING WITH SIG FIGSType of calculation Rule exampleAddition or subtraction When measurements
are added or subtracted, the answer can contain no more decimal places than the least accurate measurement
97.3 + 5.85 --------- 103.15 103.2Round off
Multiplication or division
The final answer has the same number of sig figs as the measurement having the smallest number of sig figs.
123x 5.35------------- 658.05 658 Round off
SIG FIG PRACTICE
Perform these calculations following the rules for sig figs.a. 26 x 0.02584 = ?b. 15.3 / 1.1 = ?c. 782.45 - 3.5328 = ?d. 63.258 + 734.2 = ?
SI unit – measurements in science.
VolumeDensity – m/v
A sample of aluminum metal has a mass of 8.4g. The volume of the sample is 3.1 cm3. calculate the density of aluminum.
Dimensional analysis – math technique that allows you to use units to solve problems involving measurements.
SECTION B
• Article reading
• B.1 PHYSICAL PROPERTIES OF WATER• Matter – anything that occupies space and has
mass.• Physical properties: observed and measured
without changing the substance.• Density – mass of material within a given volume.• D = m/v
WATER PROPERTIES
• Freezing point – 0 C when liquid water forms a solid.• Aqueous solution – water-based solution.• Important aqueous solutions in your life:• ____________________• ____________________• ____________________
B.3 MIXTURES AND SOLUTIONS
• Mixture – when two or more substances combine and retain their individual properties.• Heterogeneous (suspension)• Homogeneous (solution)• Solute• Solvent
• Pg.30
B.4 PARTICULATE VIEW OF WATER
• Particulate level – at the level of its atoms and molecules.• Atoms – building blocks of matter.
• Element – matter made up of only one type of atom.• Compound – composed of the atoms of two or
more elements bonded together in fixed proportions.• Ex.
• Chemical formulas – representing compounds or elements, showing ratios of how they bond.• Ex. • Substance – element or compound with uniform
and definite compositions.• Molecule – smallest unit of a molecular
compound that retains the properties of that substance.
B.5 PICTURES IN THE MIND
• Macroscopic – large-scale, easily observed without microscopes or other tools.• Models – representations of atoms and molecules.• Pg.33 ques. 1-7
B.6 SYMBOLS, FORMULAS, AND EQUATIONS
• Chemical symbols – letters to represent element.• Periodic table of the elements – arrangement
of elements according to the number of protons.
COMMON ELEMENTSAluminum Al Hydrogen HBromine Br Iodine ICalcium Ca Iron FeCarbon C Lead PbChlorine Cl Magnesium MgCobalt Co Mercury HgCopper Cu Nickel NiFluorine F Nitrogen NGold Au Oxygen OPhosphorus P Potassium KSilver Ag Sodium NaSulfur S Tin Sn
WHAT ELEMENT IS THIS?
Kpotassium
WHAT ELEMENT IS THIS?
Alaluminum
WHAT ELEMENT IS THIS?
Brbromine
WHAT ELEMENT IS THIS?
Cacalcium
WHAT ELEMENT IS THIS?
Ccarbon
WHAT ELEMENT IS THIS?
ClChlorine
WHAT ELEMENT IS THIS?
CoCobalt
WHAT ELEMENT IS THIS?
FFluorine
WHAT ELEMENT IS THIS?
AuGold
WHAT ELEMENT IS THIS?
HHydrogen
WHAT ELEMENT IS THIS?
IIodine
WHAT ELEMENT IS THIS?
FeIron
WHAT ELEMENT IS THIS?
PbLead
WHAT ELEMENT IS THIS?
MgMagnesium
WHAT ELEMENT IS THIS?
HgMercury
WHAT ELEMENT IS THIS?
NiNickel
WHAT ELEMENT IS THIS?
NNitrogen
WHAT ELEMENT IS THIS?
OOxygen
WHAT ELEMENT IS THIS?
PPhosphorus
WHAT ELEMENT IS THIS?
AgSilver
WHAT ELEMENT IS THIS?
NaSodium
WHAT ELEMENT IS THIS?
SSulfur
WHAT ELEMENT IS THIS?
SnTin
WHAT IS THE ATOMIC NUMBER?
O – Oxygen8
WHAT IS THE ATOMIC NUMBER?
C – Carbon6
WHAT IS THE ATOMIC NUMBER?
H – Hydrogen1
WHAT IS THE ATOMIC NUMBER?
Au – Gold79
WHAT IS THE ATOMIC NUMBER?
N – Nitrogen7
B.8 ELECTRICAL NATURE OF MATTER
• Electrons – negatively charged particles• Protons – positively charged particles, in nucleus• Neutrons – neutral particles, in nucleus
B.9 IONS AND IONIC COMPOUNDS
• Ions – electrically charged atoms or groups of atoms.• Ionic compounds –
substances composed of positive and negative ions• Cation – positive ion Na+• Anion – negative ion Cl-• Polyatomic ion – ion
consisting of a group of bonded atoms
B.11 WATER TESTING
• Precipitate – insoluble material in water.• Qualitative test – looking at non numerical
descriptions.• Quantitative tests – numerical data.
• Ionic compounds• Metal + nonmetal
B.12 PURE AND IMPURE WATER
• Pg. 45• Gases in atmosphere dissolve in water, nitrogen,
oxygen, carbon dioxide• 46-47 Read
SEC. C INVESTIGATING THE CAUSE OF THE FISH KILL
• Solubility – substance that will dissolve in water.• Saturated – maximum quantity of a substance
that will dissolve in a quantity of water.• What effects solubility?
• Solubility curve – relationship between temperature and solubility
• Unsaturated solution – solution that contains less dissolved solute than the amount that the solvent can normally hold at that temperature.• Supersaturated solution – unstable solution
that contains more solute than could usually be dissolved at that temperature.• Ex. Rock candy (pg.55)
C.4 DISSOLVING IONIC COMPOUNDS
• Form ions in water• Polar molecule – electrons are not evenly
distributed throughout its structure.• Partial positive region and partial negative region.• Ex. water
DIATOMICS
Reactant and Products are shown in chemical equationsReactant are the substances that are used to make a chemical reaction Products are substances produced by the reaction Na + Cl ---> NaCl reactant --> products
Diatomic Molecules - some elements bond to themselves, like H2
GEN-U-INE diatomic molecules U should remember that the diatomic molecules all end in -GEN or -INE(or H N F O I C B ) H2 N2 F2 O2 I2 Cl2 Br2
C.8 INAPPROPRIATE HEAVY-METAL ION CONCENTRATIONS?
• Essential Metal Ions:• Iron(II) Fe2+• Potassium K+• Calcium Ca2+• Magnesium Mg2+
Heavy-metal ions – atoms have greater masses than those of essential metallic elements, harmful to humans and other organisms. • Lead Pb2+ -bind to proteins in biological systems,• Hg2+ prevents proteins from performing their
normal task.
HEAVY METAL HARM
• Damage to the nervous system, brain, kidneys, and liver, which can even led to death.• They become concentrated within the bodies of
fish and shellfish.• Costly to remove• Hard to detect• Prevention: using alternate materials in industry.
Called Green Chemistry
LEAD IONS (PB2+)
• Latin name – plumbum• Plumber – water pipes in ancient Rome were
commonly made of lead.
• Used in:• Pottery, automobile electrical storage batteries, solder,
cooking vessels, pesticides, and paints
Many were replaced with iron, copper or plastic materials.1970s lead was added to gas to produce a better-burning automobile fuel. Released in atmosphere.
MERCURY IONS HG2+
• Liquid at room temp• Latin name = hydrargyrum, quicksilver or liquid
silver• Uses:• Electrical conductor, thermometers, thermostats, hats,
light bulbs, pesticides
• Vapor is hazardous, absorbed through skin
CHEMICAL POSTER
C.9 INAPPROPRIATE PH LEVELS
• pH – measure and report the acidic, basic, or chemically neutral character of a solution.• Range = 0---14• Neutral = 77> acidic7<basic (alkaline solutions)1pH unit = tenfold difference in acidity or alkalinitypH 3 soft drinks, pH 2 lemon juiceLemon juice is 10 time more acidic than soft drinks.
LITMUS PAPER
• Indicator to show level of acidity or alkalinity.• Blue – basic• Red – acidic• Acidic and basic solutions conduct electricity.• What does this tell you?• Ions present in the solution.• Acids – release H+ ions • Bases – release OH- ions
NEUTRAL SUBSTANCES
• Sucrose, sodium chloride solutions = neutral• Low pH in streams• Fish-egg development is impaired• Increase the concentrations of metal ions by leaching
metal ions from surrounding soil.
High pH in streams• alkaline solutions are able to dissolve organic
materials, including skin and scales
EPA REQUIREMENTS
• Drinking water be within the pH range of 6.5 – 8.5• Fish can tolerate 5.0 – 9.0
• Did the pH change to kill all the fish?
C.10 INAPPROPRIATE MOLECULAR SUBSTANCE CONCENTRATIONS
• Molecular substances – composed of molecules not ions.
• Molecular substances can be harmful for aquatic life.• Examples: ethanol C2H5OH, succinic acid C4H6O4,
carbon dioxide CO2, oxygen gas O2• What determines the solubility of a molecular
substance in water?• Distribution of electrical charge within molecules.• Electronegativity – ability of an element’s atoms
to attract shared electrons when bonding within a compound. causes e- to be unevenly distributed among the atoms.
POLAR MOLECULE
• Negative and positive side of a molecule.• “like dissolves like”• Polar dissolves polar• Nonpolar dissolves nonpolar• Ex. Oils, soaps soap attracts oils
C.11 SOLVENTS
• Soluble – will dissolve• Insoluble – will not dissolve
C.12 INAPPROPRIATE DISSOLVED OXYGEN LEVELS?
• As temperature goes up less oxygen is dissolved.• Gas solubility in water is directly proportional to
the pressure of that gaseous substance on the liquid.• Increase in water temperature affects fish by
decreasing the amount of dissolved oxygen in the water and by increasing the oxygen consumption of fish.